The girls apparently were stranded in a car with their mother after the car ran out of gas

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Madison Owens, 11, (far left) and her 9-year-old twin sisters, Nicole (center) and Kristin Owens (bottom right), were last seen with their mother, Stephanie Owens (inset), on April 24.

Four members of a southwest suburban Crestwood family have been found safe after Illinois State Police issued an "endangered missing person advisory" on Thursday.

Madison Owens, 11, and her 9-year-old twin sisters, Kristen and Nicole Owens, were found Friday morning in a car with their mother, the girls' father, Dwayne, told NBC Chicago. He said the car had run out of gas and their mom's debit card had been declined.

Dwayne Owens was told they had been stranded in the car for at least a day. "A big, huge relief crossed over me," he said after hearing the news that they were OK.

The girls were last seen with their mother, Stephanie Owens, on Sunday at their Crestwood home.

The family has lived with Stephanie Owens' brother for about the last 18 months, the girls' uncle told authorities. He said he didn't think anything of not seeing his nieces on Monday because they had off of school and he assumed they were with their mother.

He alerted authorities on Wednesday when the family still hadn't turned up, adding that his sister seemed depressed and distraught when he last saw her.

In their investigation, authorities started calling other family members. The girls' grandmother reported received a text message from the young girls:

"Hi mom. We are not having Easter because God told mommy not to. Also, Happy Easter. But guess what if you don't do Easter you get to see God."

"I'm very scared for my grandchildren. [Stephanie Owens] is truly a wonderful person. She has a heart of gold, but I'm afraid of what she's going to do," the grandmother, Cheryl McKinney, tearfully told NBC Chicago via telephone. "I never in my wildest dreams imagined I'd see one of my children or my grandchildren on one of those [missing persons] flyers."

Investigators looked into email messages and Facebook messages that may have been traded between Stephanie Owens and a Facebook friend in California.

"The Facebook friend didn't put too much weight into these messages, the emails going back and forth, until now, now that she's missing. She talks about God, talks about the Devil and something big that's going to happen," said Theresa Neubauer, Crestwood's police chief.

The four were believed to be traveling in a 1996 silver Lexus four-door with Illinois license plates L321854.

The vehicle was last reported being seen by police in Abingdon, about 50 miles east of the Iowa/Illinois border. The vehicle was parked, unoccupied, in the American Legion parking lot at the time but was no longer there.

Cell phone records indicated the phones have been powered off since Monday.